en
Scientific article
Open access
English

A theoretical investigation of the enantioselective hydrogenation mechanism of alpha-ketoesters

Published inJournal of molecular structure. Theochem, vol. 330, no. 1-3, p. 353-357
Publication date1995
Abstract

The enantioselective hydrogenation of α-ketoesters to α-hydroxyesters over Pt/Al2O3 catalysts modified by cinchona alkaloids is an interesting model reaction for the investigation of heterogeneous catalysis capable of producing optically active products. The aim of the present theoretical study is to rationalize the interaction between protonated cinchona alkaloids (modifiers) and methyl pyruvate (substrate) by investigating the possible weak complexes formed by these two species. For this purpose we use molecular mechanics and the AM1 semiempirical method. The optimization leads to two stable forms of the complexes, where the substrate is bound to the modifier via hydrogen bonding between the oxygen of the α-carbonyl of pyruvate and the quinuclidine nitrogen of the alkaloid. In such complexes the methyl pyruvate is transformed into a half-hydrogenated species which can be adsorbed on the platinum surface and, after hydrogenation, leads to methyl lactate product. The results show that adsorption of the complex leading to (R)-methyl lactate is more favorable than that of the corresponding system yielding (S)-methyl lactate, which may be the key for the enantio-differentiation.

Research group
Citation (ISO format)
SCHWALM, Olivier et al. A theoretical investigation of the enantioselective hydrogenation mechanism of alpha-ketoesters. In: Journal of molecular structure. Theochem, 1995, vol. 330, n° 1-3, p. 353–357. doi: 10.1016/0166-1280(94)03860-N
Main files (1)
Article (Published version)
accessLevelPublic
Identifiers
ISSN of the journal0166-1280
525views
187downloads

Technical informations

Creation09/21/2009 4:04:09 PM
First validation09/21/2009 4:04:09 PM
Update time03/14/2023 3:12:15 PM
Status update03/14/2023 3:12:15 PM
Last indexation01/15/2024 6:49:56 PM
All rights reserved by Archive ouverte UNIGE and the University of GenevaunigeBlack